After Adam and Eve’s sin in the garden, God predicted that mankind would fall into one of two camps. They would either be the offspring of the serpent, or the offspring of the woman:
“I will put enmity between you and the woman, and between your offspring and her offspring;” (Gen. 3:15 ESV)
This divergence began when Cain murdered his brother, thereby choosing to carry out the will of his spiritual father, the devil. The serpent’s offspring are all those who oppose God. This is why Jesus called the Pharisees the offspring of the devil.
You are of your father the devil, and your will is to do your father’s desires. He was a murderer from the beginning, and does not stand in the truth, because there is no truth in him. When he lies, he speaks out of his own character, for he is a liar and the father of lies. (John 8:44 ESV)
Family feud
In murdering his brother Cain revealed his true nature and in rejecting God’s admonition and correction, he became the offspring of the serpent. Cain was a murderer just like his father the serpent.
Cain’s reaction to the penalties of his crime was to think only about himself. He whined about the inconveniences, and the consequences, his deed would bring (Gen 4:13-14). With no expression of remorse, he goes east leaving the presence of God (Gen 4:16).
The narrative goes on to list the descendants of Cain (Gen 4:17-22). We also learn that Adam and Eve have another son named Seth and his descendants are also named (Gen 4:25-5:32). How do Cain and Seth’s children turn out? We can’t tell anything about their character just by knowing their names.
The apple doesn’t fall far from the tree
To answer this question, the author of Genesis pauses the genealogies to give us a very brief, yet revealing, glimpse into the characters of the seventh descendants of Adam from both lines: Lamech (Gen 4:19-24) and Enoch (Gen 5:21-24).
Lamech is a descendant of Cain, the sixth generation from Adam. The story tells us that Lamech was wounded by someone, and killed him in revenge. Lamech wasn’t interested in an “eye for an eye,” but “a life for an eye.” He boasted to his wives that he will outdo even God when it comes to vengeance. God promised Cain that if anyone hurt him in retribution for Abel’s murder, God would exact vengeance sevenfold (Gen 4:15). Lamech boasts that anyone who crosses him will not receive seven times the vengeance, but seventy-seven times!
Enoch walked with God
Enoch is a descendant of Seth, also the sixth generation from Adam. What kind of man has Enoch turned out to be?
Enoch is pictured as one who did not suffer the fate of Adam (“you shall surely die”) because, unlike the others, he “walked with God.” The sense of the author is clear. Enoch is an example of one who found life amid the curse of death. In Enoch the author is able to show that the pronouncement of death is not the last word that need be said about a person’s life. One can find life if one “walks with God.” For the author, then, a door is left open for a return to the Tree of Life in the Garden. Enoch found that door in his “walking with God” and in so doing has become a paradigm for all who seek to find life. It is significant that the author returns to this theme at the opening of chapter 17, where God establishes his covenant promise with Abraham. Here the meaning is clear: “walk before me and be perfect, and I will establish my covenant with you” (17:1– 2). To “walk with God” is to fulfill one’s covenant obligations.1
The sons of God versus the sons of the devil
The author of Genesis is highlighting Lamech and Enoch as representatives of their respective branches of the family. By comparing the character traits of these two representatives, Moses is revealing to his readers that Cain’s family line followed in their father’s footsteps. Like Cain, they are cruel and vindictive and show that they are the offspring of the serpent.
In contrast, Seth’s family line were people of faith who sought after God. Enoch walked with God. Only two men in the entire Bible are explicitly said to have “walked with God”. Enoch was one, and Noah was the other (Gen 6:9). The Scripture implies that Abraham also walked with God (Gen 17:1), but this is not explicitly stated.
A contrast is being established between these two branches of Adam and Eve’s family. Seth’s branch describes the line God chose which would ultimately produce the “seed of the woman” (Gen 3:15) who would defeat the serpent and the serpent’s offspring. The distinction between these family lines will figure prominently in the generations leading up to Noah’s flood.
Spiritual warfare
Everything else that follows in the Bible will record the struggle between the offspring of the woman and the offspring of the serpent. This struggle is still going on today and will continue until the end when God will finally be victorious over the forces of evil.
One does not have to actively pursue evil to be a child of the devil. One may passively carry out the devil’s will simply by not being a committed follower of Jesus. We are engaged in a spiritual battle (Eph 6:12) and there is no such thing as a neutral observer. We are either on God’s side, or we are on the devil’s side. The choice of who we serve is up to us.